Method and apparatus for mixing, grading, and sorting granular and pulverulent material



E. SPRENGER IXING, GRADING, AND SORTING G-RANULAR AND Filed Dec. 8, 1921PULVERULENT MATERIAL METHOD AND APPARATUS FOR M July '19, 1927.

mmron M M7 ATTORNEYS Patented July 19, 1927.

UNITED STATES PATENT oFr cE.

EMILE SPRENGEB, or .GOLYDAACIVI, swi-rznm a vn METHOD AND APPARATUS FORMIXING, GRADING, Ann sonrnve GRANULAR AND PULVERULENT MATERIAL.

Application filed December a, 1921.. sw rm. 520,820.

This invention is applicable for the treatment of practically any kindof granular or pulverulent material, including for example hydraulicbinding agents, cement materials, powdered gypsum lime, chemicals suchas are used in the manufacture of colorsand other substances, coal andfor briquet manufacture. The mixing and sorting may be independentoperations, or they may beconourrent operations as when severalmaterials areyfirst intimately mixed and then subjected to a separatingor sorting action, whereby the mixture is divided up according to thedegree of fineness of the particles.

I secure the grading orsorting ot' the pul verulent materials accordingto the varying degrees of fineness by using a blast of air or othergaseous medium which carries the finer and coarser or heavier particlesdifferent dis tances. vention I prevent the spent air or gaseous mediumfrom contaminating the atmos' phere; I avoid the trouble, expense andinconvenience or cleaning it or leading it away to a place where itisinnocuous; and I avoid the very appreciable loss of material in theform of dust carried away the gaseous medium and which cannot be whollyrecovered economically.

In carrying out my invention the material is treated in whole 01' inpart by a centrifugal distributor or fan operating in a wholly enclosedspace and arranged so that the suction due to the centrifugal apparatusdraws the air or other gaseous medium from the chamber into which itblows it. That is to say, the air is in continuous circulation in asubstantially closed cycle or system, and consequently there is nodischarge of a stream of spent air or other gas and there no loss ofdust carried away by any such spent air or gas.

Fig. 1 a vertical. longitudinal section through one form of apparatusembodying my invention,

Fig. 2 is a vertical transverse section taken substantially on the line22 of Fig.1,

Fig. 3 is a horizontal section of part of the apparatus, taken throughthe fan shaft.

The apparatus shown in Figs. 1, 2 and 3 includes a box or chamber 1,serving as a receptacle to receive the mixed or graded ma terials andhaving fitted to one end thereof ahousing or casing 2 for thecentrifugal dis- As one important object of my in tributor or fan Thebox or receptacle may be made of two parts, the upper part beingremovable or hinged to give convenient access to the interior thereof.The box may be of any desired cross sectional form as for instancerectangular, as indicated in Fig. 2, or it may be a cylindrical drum orreceptacle of other shape.

Within the receptacle there are a plurality of transverse wallsextending upwardlytrom the bottom to only apart of the height of thereceptacle, and dividing the lower partinto a series of compartments orsubreceptacles a, b, 0, (Z, c, f, g, h, 2', all open at the top. Ifdesired the distance of 'these partitions from the distributor and fromeach other may be varied in accordance with the number of grades intowhich it is desired to sort the material. As shown. the compartments areof different sizes and the partitions nearer the distributor are of lessheight than those at a greater distance therefrom. The difference in thesizes of the compartments may also be accomplished in part by a slopingof the wholeor a portion of the floor of the receptacle. '1 do not wishto be restricted to any particular arrangement or formation of thesecompartments except that they be at varying distances from thedistributor and that the space above them be open so that the heaviestparticles may fall into the nearest compartment, and the othercompartments at varying distances receive the particles correspondinglyvarying in size. The finest dust collects in the receptacle tarthestfrom the distributor.

The centrifugal distributor may consist ot a disk \vithvanes 4 rotatableabout a hori-' zontal axis and receiving the granular or pulverulentmaterial from a feeder 5 and hopper 6 through a substantially verticalfeed duct 7 If it is desired to merely sort.

or grade one material according to the fineness otthe materials, onlythis one material maybe placed in the hopper 6. If it is desired todifierent materials at the same time that the mixture is sorted orgraded according to fineness, the hopper may have or mixture ofmaterials to drop through the feed duct to the distributor.

The casing 2 and the centrifugal distributor or fan 3 are so designedthat a bypass is formed and air or other gaseous medium withdrawn fromthe feed duct and blown into the receptable 1 may return to the feedduct for recirculation through the distributor. As shown particularly inFigs. 2 and 3, the vanes do not extend all the way from the disk to theopposite side of the casing and are of substantially triangular form.Thus there is no danger of coarse particles of the material wedgingbetween the wall of the casing and the distributor or fan blades. Theair, returning from the receptacle past the fan, for recirculationthrough the latter, acts on the material in the lower portion of thefeed duct 7 and agitates this material so as to effect a pretreatment ofit or a partial mixing of the different kinds of material, if these bedifferent kinds in the separate compartments of the hopper 6. The upwardblast in the feed duct also tends to give a preliminary separation byretarding the lighter particles descending from the feeding device 5.

The final separation is effected by centrifugal apparatus, the blades ofwhich throw the material into the receptacle 1, the various particlesbeing projected to different distances according to their specificweights and varying degrees of fineness, or both. The process of sortingis thus effected in the box, and the materials are graded out in thecompartments a, Z), 0, etc. It will be understood that if a plurality ofdifferent kinds of material be delivered from the hopper 6, there willbe not only a sorting according to the fineness, in the receptacle 1,but there will also be a bringing together or mixing of the particles ofeach material with the corresponding size of particles of the othermaterial or materials.

Gases other than air might be introduced and circulated without loss,and these gases might be of such character that they would have chemicalaction on the material, or might be gases devoid of oxygen so as toavoid oxidation of the materials. F or this purpose the separator has achamber 8 annexed thereto and a door 9 fastened by catches 10 forpermitting access to this chamber at any time during working operations.If such gases are used they are introduced by means of a pipe into achamber 8, annexed to the casing 2 of the centrifugal separator 3.Normally, however, the process is performed in an atmosphere of aircontained in the chamber 1, casing 2, and chamber 8, the wall of thechamber 1 having an opening to the chamber 8, laterally of the casing 2,and the latter having an opening to the chamber 8, in front of the ringof fan blades 4 whereby the granular material is projected into thechamber 1. A gentle circulation of air is set up by the centrifugaldistributor, air passing out of the casing 2 into the chamber 1 anddrifting back, laden with fine dust, along the walls and roof, to theopening leading to the chamber 8. From this chamber 8 the dustladen airreturns to the casing 2, entering the vortex within the ring of blades,and the dust which it carries is mingled with the material on which theblades are acting. The chamber 8 can be swung aside on a hinge 9, but isnormally held against the chamber 1 by catches 10. Any suitable powermechanism may be employed for operating the distributor and rotaryfeeding device. Merely as an example I have illustrated a driving pulley11, the shaft 13 of which actuates the feeder 5 by means of intermeshinggears 12 and 12. The centrifugal distributor is driven by powertransmitting mechanism including a sprocket ll, a chain 16, a sprocket15, a gear 17 and a pinion 17. The pulley ll may be driven by anysuitable prime mover or manually, depending upon the size of themachine.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:*

1. Apparatus for mixing and grading granular materials, comprising incombination a horizontal grading chamber having an outlet aperture atone end thereof, a centrifugal distributor, a casing for saiddistributor having a delivery aperture facing a portion of thedistributor circnmference and opening into said chamber, a feed aperturefacing another portion of the dis tributor circumference, and an intakeaperture facing one side of the distributor, and a box open to theoutlet aperture cf said chamber and to the intake aperture of saidcasing.

2. "he method of mixing and grading granular materials, consisting iniinpartiing circulation to a substantially closed system of gaseousmedium in a path in all parts of which the medium is capable of carryingsolid particles in suspension, and delivering the materials to thestream of gaseous medium at one part of said path, from which all theparticles are carried by the gas in one direction and to which the finerparticles are returned in the opposite direction.

EMILE SPRENGER.

